Excel 2007 : adding text to string

Hello!
I have 2 columns of cells with hundreds of rows. One column contains the name of a picture file, and the other column contains a string that points to the location of that picture. The path is the same on every row. The only difference is the name of the picture.
How can I change only the part of the text string in column 2 that shows the picture name, to read from the cell in the first column?

example:

Column1
sample_pic.gif

Column2
c:\workspace\images\sample_pic.gif


Any help would be much appreciated.
Thanks!